/* 
* @Author: anchen
* @Date:   2018-04-26 15:00:34
* @Last Modified by:   anchen
* @Last Modified time: 2018-04-26 15:02:57
*/

'use strict';
var arr=[[1,2],[3,4]]
var arr2=[1,2]
var index=arr2.indexOf(2)
console.log(index)